Method of making an integrated circuit including structuring a material

ABSTRACT

A method of making an integrated circuit including structuring a material. The method includes providing an arrangement of three-dimensional bodies. The material is arranged between the bodies and structured directed radiation. The projection pattern of the three-dimensional bodies is transferred into the material. The structured material connects at least two of the three-dimensional bodies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Application No. 10 2007 022748.7-43 filed May 15, 2007, which is incorporated herein, in itsentirety, by reference.

BACKGROUND

The following description relates to the technical field ofsemiconductor components, specifically it refers to a method ofstructuring a layer in a semiconductor component.

In the following context the term “semiconductor component” relates ingeneral to integrated circuits, chips, as well as single semiconductorcomponents like for example analog or digital circuits or singlesemiconductor components like semiconductor memory elements, forexample, functional storage components (PLAs, PALs etc.) and arraystorage elements (ROMs or RAMs, especially SRAMs and DRAMs).

Beside other applications, for example, micromechanical components, themethod of structuring can be used to manufacture stabilizing supportstructures of capacitors of DRAM-components. According to the cellconcept one may distinguish between trench capacitors and stackcapacitors. Trench capacitors are formed in the substrate and thereforeare arranged underneath the selection transistors of the respectivecell. On the other hand, stack capacitors are arranged above thesubstrate and above the selection transistors.

In terms of shape, both capacitor types may have a cylindrical form. Thecross section may be round or elliptical and does not need to be of thesame shape over the axial course of the capacitor. For sake ofsimplicity, the shape is referred to as tube, whereas different areasand sizes of cross sections at different axial positions are possible.Furthermore the tubes may include an overhang, i.e. they may have alarger cross section in a top portion compared to a lower portion.

To increase the capacitance of a capacitor C

$C = {ɛ_{o}ɛ_{r}\frac{A}{d}}$with the surface A, the distance between the electrodes d and thedielectric constant ∈_(r), various measures are applied. One measure maybe the increase of the aspect ratio of the capacitor tube and therebythe increase of the capacitor surface A.

The structure of the stack capacitors above the substrate leads to theproblem of mechanical stability of the capacitor arrangement. Forexample, a process using liquids (e.g., a wet etch or a wet rinse) maylead to a collapse of the tubes due to capillary forces.

Various techniques are applied for the mechanical stabilization of thestack capacitor.

In general, support structures are introduced which are arranged in anupper portion of the capacitor tube and which connect adjacent tubeswith each other. This may prevent a bending of the capacitor tubes.However, it must be ensured that the material underneath the supportstructure can be at least partly removed. To achieve this, a structuringof the support material needs to be done in order to create openings.

One possibility to structure the support material is the use of the socalled mask process. In a first step, a photoresist is deposited. Theresist is exposed through a mask and the exposed or unexposed parts ofthe resist are removed. The structure of the resist layer is transferredin a subsequent step into the support material. Disadvantage of such amethod is the need of a mask for this process and additional steps likethe deposition of the photoresist, the exposure and the structuring ofthe resist, etc. are required. This impacts the cost of such amanufacturing process of a semiconductor component.

Kim et al., “A Mechanically Enhanced Storage Node for Virtuallyunlimited Height (MESH) Capacitor Aiming at sub 70 nm DRAMs”, IEDM Tech.Dig., p. 69-72 (2004) illustrates a support structure of a stackcapacitor made from silicon nitride. The structuring of the supportstructure is performed by using the so called spacer technology. Aconformal silicon nitride layer is deposited onto the capacitor tube.The support material is subsequently structured by using dry etch step.Using this method, the structuring is self aligned and no mask step isrequired.

A similar process is proposed by Manning in U.S. Pat. No. 7,067,385. Aspacer is used for the structuring of the support material as well.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 illustrates a schematic representation of a perspective view ofan arrangement of three-dimensional bodies with material between thethree-dimensional bodies and a directed radiation.

FIG. 2 illustrates a schematic representation of a perspective view ofan arrangement of tubes with a material between the tubes and directedradiation.

FIG. 3 illustrates a top view of an arrangement of tubes with aprojection pattern after a directed radiation from a first direction.

FIG. 4 illustrates the same top view as FIG. 3 after a directedradiation from a second direction.

FIG. 5 illustrates a top view of an arrangement of tubes with aprojection pattern after directed radiation from two differentdirections.

FIG. 6A illustrates a side view of two adjacent tubes and with amaterial between these two tubes prior to a directed radiation.

FIG. 6B illustrates a side view of two adjacent tubes and with materialbetween these two tubes after removing the material exposed during theradiation.

FIG. 7A illustrates a further implementation with a first material and asecond material arranged between two adjacent tubes and prior to adirected radiation.

FIG. 7B illustrates a further implementation with a first material andsecond material arranged between two adjacent tubes and after removal ofthe material exposed during the radiation.

FIG. 8 illustrates a top view of an arrangement of tubes with aprojection pattern after directed radiation from a first direction.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withreference to the orientation of the Figure(s) being described. Becausecomponents of embodiments can be positioned in a number of differentorientations, the directional terminology is used for purposes ofillustration and is in no way limiting. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention. Thefollowing detailed description, therefore, is not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims.

It is to be understood that the features of the various exemplaryembodiments described herein may be combined with each other, unlessspecifically noted otherwise.

As described in complete detail below, one embodiment of a method ofmaking an integrated circuit or device including a the method forstructuring a material includes:

providing an arrangement of three-dimensional bodies with the materialbetween the bodies;

structuring the material by directed radiation,

whereby the projection pattern of the three-dimensional bodies istransferred into the material and the material connects at least two ofthe three-dimensional bodies.

The term “connecting” does not only refer to the direct mechanicalcontact between the three-dimensional bodies, but may in a wider meaningalso refer to three-dimensional bodies being coupled. In this case, afurther material may be arranged between three-dimensional bodies inaddition to the structured material. It is also be possible, that a gapexist between the three-dimensional bodies and the structured material.

The directed radiation may, for example, include radiation with ions,electrons or photons. When using ions, the ions may substantially haveone direction and may be selected from the group of BF₂, B, P, As, Ge,N₂, N, C, Si, F, In, Sb, He, Ne, Ar, Kr, Xe, or Rn.

The three-dimensional bodies may be formed as tubes. The tubes mayinclude a round or elliptical cross section and may include an overhang.

The material between the three-dimensional bodies may, for example, beselected from the group of silicon oxide, amorphous silicon, siliconnitride or a photoresist.

The material being exposed or being not exposed by the directedradiation and arranged between the three-dimensional bodies may beremoved in a separate process step.

In one embodiment, the material between the three-dimensional bodies mayhave a higher removal rate after the directed radiation compared to theremoval rate before the radiation.

In one embodiment, the material between the three-dimensional bodies mayalso have a lower removal rate after the directed radiation compared tothe rate before the radiation.

The material between the three-dimensional bodies can be removed in aseparate process using a liquid which may be selected from the group ofammonia, hydrofluoric acid or a solvent to develop a photoresist.

The material between the three-dimensional bodies may be removed byusing a plasma in a separate process.

The material between the three-dimensional bodies may be eroded by thedirected radiation.

The arrangement of three-dimensional bodies may be an arrangement ofstack capacitors and the material between the three-dimensional bodiesmay be a support structure between the stack capacitors. The materialbetween the three-dimensional bodies can as well be used to structure asecond material; the second material then forming the support structurebetween these stack capacitors.

One embodiment provides a material which is structured by a projectionof an arrangement of three-dimensional bodies by directed radiationwherein the projection pattern of the three-dimensional bodies istransferred into the material and the material connects at least two ofthe three-dimensional bodies.

One embodiment provides an arrangement of stack capacitors with amaterial being structured by projection of an arrangement of stackcapacitors by directed radiation, wherein a projection pattern of thestack capacitors is transferred into the material and the materialconnects at least two of the stack capacitors. The material between thestack capacitors may as well be used to structure a second material.

One embodiment provides an integrated circuit, which includes amaterial, the material being structured by the inventive method. Theintegrated circuit may at least include two stack capacitors and a stackcapacitor and a material which has been structured by the inventivemethod.

One embodiment provides a DRAM component including stack capacitorswhich are connected by a material which has been structured by theinventive method.

The invention is described in detail in the following with reference tothe drawings. The drawings illustrate embodiments of the invention.However, the invention can be realized in various implementations and itis not intended to limit the invention to the implementationsillustrated. Moreover, the implementations serve to formulate thedisclosure in a diligent and accurate manner and to enable the personsskilled in the art to exercise the invention. The drawings are not toscale, but shall illustrate the necessary elements for understanding theinvention in a schematic way. The layer thicknesses are not to scale, aswell as the diameters and heights of the three-dimensional bodies ortubes, and therefore as well their aspect ratio. The angle of theradiation is arbitrary and is illustrated to demonstrate the inventiveprinciple.

FIGS. 1 and 2 illustrate a general arrangement to represent theinventive concept. An arrangement of three-dimensional bodies 110 with amaterial 120 in between is subjected to directed radiation 130. It isintended to structure the material 120 between the tubes 110 by usingthe inventive concept.

The inventive concept is discussed in more details in FIG. 2 accordingto one embodiment using tubes as three-dimensional bodies 110 and usingdirected radiation 130 by ions, electrons or photons.

A projection pattern 103 is generated on the material 120 by thearrangement of tubes 110 subjected to the directed radiation 130. Theprojection pattern depends on the angle of incidence of the directedradiation 130 and the structure and arrangement of the tubes 110.

FIG. 3 illustrates an example of a top view of the arrangement of tubes110 with a projection pattern 103 after directed radiation 130 from afirst direction. The projection pattern of the tubes 110 is transferredinto the material 120.

In one embodiment, the removal rate of the material 120 is modified bythe radiation 130. On the one hand, it is possible that the material 120has an increased removal rate after radiation 130 compared to the samematerial 120 without radiation 130. In a subsequent process, thisselectivity of the removal rate is used to remove the material 120 beingirradiated by the ions 130. The remaining structure 103 of the material120 shall be structured so as to generate a connection between at leasttwo of the tubes 110 by the material 120.

The term “connect” is not limited in this case to direct contact betweenthe three-dimensional bodies 110 but may also mean that thethree-dimensional bodies 110 are coupled with each other. In this case,a further material can be arranged between the three-dimensional bodies110 in addition to the structural material 120. It is as well possible,that a gap between the three-dimensional bodies 110 exist in addition tothe structured material 120.

The term “removal rate” is intended to have a general meaning. Theexposed or non exposed material 120 can be removed for examplechemically, mechanically, by use of a solvent or a developer.

In one embodiment, the removal rate of the material 120 is modified bythe radiation 130. It is as well possible that the material 120 may havea lower removal rate after radiation 130 compared to the same material120 without radiation 130. In a further step, this selectivity of theremoval rate is used to remove the material 120 not irradiated by theions 130. The remaining structure 103 of the material 120 shall bestructured so as to form a connection between at least two tubes 110 bythe material 120.

In one embodiment, a liquid may be used to remove the material 120irradiated by ions 130.

In one embodiment, a “dry etching step” using a plasma can be used toremove the irradiated or non-irradiated material 120. In this case, theremoval through an isotropic etch component can be done by radicalsgenerated in a plasma. It is as well possible to use a removal by ananisotropic etch component from accelerated ions of a plasma boundarylayer. A combination of isotropic and anisotropic components may be usedto remove the irradiated or the non-irradiated material 120 by using aplasma.

In one embodiment, the material 120 is eroded directly through theradiation 130. Ions may be used for the radiation 130. The material 120irradiated by the ions 130 will thereby be removed. The remainingstructure 103 of the material 120 shall be formed so as to connect atleast two tubes 110 by the material 120.

FIG. 4 illustrates, for example, a top view of an arrangement of tubes110 with a projection pattern 103 after radiation 130 from a seconddirection. The projection pattern 103 of the tubes 110 is transferredinto the material 120.

FIG. 5 illustrates, for example, a top view of an arrangement of tubes110 with a projection pattern 103 after radiation 130, wherein theradiation 130 is performed from two different directions. The radiation130 can be performed in parallel from two different directions orsequentially using two subsequent processes.

The combination of different angles of incidence of the ions anddifferent directions may not be limited. They may be selected to providea projection pattern 103 which is optimized for the underlyingapplication in order to form a connection between at least two tubes bythe material 120.

FIGS. 6A and 6B illustrate a side view of two adjacent tubes 110 a and110 b with a material 120 arranged between this two tubes prior to aradiation 130, and after removal of the material exposed to theradiation, respectively. The directed ions 130 are blocked by the righttube 10 b thereby forming two areas of different exposure in thematerial 120. The area 103 of the material 120 is irradiated by the ions130, while the remaining material 120 is not.

FIGS. 7A and 7B illustrate a similar side view compared to FIGS. 6A and6B of two adjacent tubes 110 a and 110 b with a first material 120arranged between these two tubes and a second material 121 underneaththe first material 120. The first material 120 is structured using theinventive concept, and may be used as a hard mask for structuring thesecond material 121.

The shape of the tubes 110 can have a constant cross section along theaxial course or may vary over it. The tubes 110 may have a larger crosssection in a portion above the material 120 compared to a portionlocated directly at the material 120, i.e. they may form an overhangabove the material 120. The method is suitable for the projection ofthree-dimensional bodies 110 having an arbitrary shape.

The inventive structuring method can be used to manufacture supportstructures of capacitors of DRAM components. These capacitors may be socalled “stack capacitors” which require a support structure formechanical stabilization.

The material 120 forms in this case the support structure. The tubes 110form, at least partially, the stack capacitors. The tubes 110 may inthis case form the first electrode of the stack capacitors. The firstelectrode is formed in a fill material, also called mould material. Inan upper portion of the first electrode, a layer or a system of layersis deposited, which later forms the support structure.

In order to be able to remove the mould material at least partially in asubsequent step, the layer or the system of layers of the supportstructure needs to be structured. It may in this case be advantageous toprovide openings of maximum width in order to be able to remove theunderlying mould material in the easiest possible way. With the help ofthe inventive method the structuring of the support structure of stackcapacitors may be performed in an advantageous way.

The stack capacitors may be present in various different two-dimensionalarrangements. One arrangement may be a hexagonal pattern. It ispossible, that this pattern is not a purely periodic arrangement, butthe pattern may include periodic and non-periodic regions as well.

The material 120 may be selected from the group silicon oxide, amorphoussilicon, silicon nitride or a photoresist. Silicon nitride may haveadvantages when forming stack capacitors.

The ions may be selected from the group of BF₂, B, P, As, Ge, N₂, N, C,Si, F, In, Sb, He, Ne, Ar, Kr, Xe or Rn. From this group the elementsHe, Ne, Ar, Kr, Xe or Rn may be advantageously used in the case of adirect erosion of the material 120 according to an implementation ofclaim 15. For example, Ar may be used due to its inert properties andthe mass adaption for mechanical removal, so called “sputtering”. In oneimplementation, a liquid selected from the group of ammonia,hydrofluoric acid, or a developer of photoresist may be used in theselective removal of the material 120.

FIG. 8 illustrates, for example, a top view of an arrangement of tubes110 with a projection pattern 103 after directed radiation 130 from onedirection. The projection pattern 103 of the tubes 110 are transferredinto the material 120. In this case, the projection pattern 103 is onlyconnected directly with one of the tubes 110 and the tubes 110 arecoupling with each other through a gap. This gap may be filled with amaterial. In the case that the gap is not filled, the tubes 110 areallowed to move sideways, but are limited in sideway movement by thematerial 120.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

1. A method of making an integrated circuit including structuring amaterial, the method comprising: providing an arrangement ofthree-dimensional bodies with the material arranged between the bodies;and structuring the material by directed radiation, whereby theprojection pattern of the three-dimensional bodies is transferred intothe material and the structured material connects at least two of thethree-dimensional bodies.
 2. The method of claim 1, wherein the directedradiation comprises a radiation by one of the group of ions, electrons,or photons.
 3. The method of claim 2, wherein the radiationsubstantially has one direction.
 4. The method of claim 2, wherein thedirected radiation comprises a radiation with ions selected from thegroup of BF₂, B, P, As, Ge, N₂, N, C, Si, F, In, Sb, He, Ne, Ar, Kr, Xe,or Rn.
 5. The method of claim 1, wherein the three-dimensional bodiescomprise tubes.
 6. The method of claim 5, wherein the tubes comprisehaving a round or an elliptical cross-section.
 7. The method of claim 5,wherein the tubes comprise having an overhang.
 8. The method of claim 1,comprising selecting the material arranged between the structures fromthe group of silicon oxide, amorphous silicon, silicon nitride, or aphotoresist.
 9. The method of claim 1, comprising modifying a removalrate of the material by the directed radiation and one of the exposed ornon-exposed portions of the material is removed in a separate process.10. The method of claim 9, wherein the material arranged between thethree-dimensional bodies comprises a material with a higher removal rateafter radiation compared to the removal rate prior to radiation.
 11. Themethod of claim 9, wherein the material arranged between thethree-dimensional bodies comprises a material with a lower removal rateafter radiation compared to the removal rate prior to radiation.
 12. Themethod of claim 9, comprising removing in the separate process thematerial using a liquid.
 13. The method of claim 12, comprisingselecting the liquid from the group of ammonia, fluoric acid, or adeveloper for photoresists.
 14. The method of claim 9, comprisingremoving in the separate process the material using a plasma.
 15. Themethod of claim 1, comprising eroding the material by the directedradiation.
 16. A method of making an integrated circuit includingstructuring a material, the method comprising: providing an arrangementof three-dimensional bodies with the material arranged between thebodies; and structuring the material by directed radiation, whereby theprojection pattern of the three-dimensional bodies is transferred intothe material and the structured material connects at least two of thethree-dimensional bodies, and wherein the arrangement ofthree-dimensional bodies forms part of stack capacitors and the materialforms part of a support structure arranged between the stack capacitors.17. A method of making an integrated circuit including structuring amaterial, the method comprising: providing an arrangement ofthree-dimensional bodies with the material arranged between the bodies;and structuring the material by directed radiation, whereby theprojection pattern of the three-dimensional bodies is transferred intothe material and the structured material connects at least two of thethree-dimensional bodies, and wherein the arrangement ofthree-dimensional bodies forms stack capacitors and the material is usedto structure a second material forming a support structure arrangedbetween the stack capacitors.
 18. An integrated circuit comprising: amaterial, wherein the material is structured by the method of claim 1.19. An integrated circuit comprising: at least two stack capacitors anda material, wherein the material is structured by the method of claim 1.20. A device comprising: a DRAM component with a plurality of stackcapacitor being connected by a material, wherein the material isstructured by the method of claim 1.